1. Field of the Invention
The present invention relates to magnetostatic wave devices, and, more particularly, to magnetostatic wave devices comprising Y.sub.3 Fe.sub.5 O.sub.12 -based magnetic garnet single crystal films.
2. Description of the Related Art
Generally, a Y.sub.3 Fe.sub.5 O.sub.12 (hereinafter referred to as YIG) single crystal, which is a type of a magnetic garnet single crystal film, is an important material for a magnetostatic wave device. In particular, an extremely small ferromagnetic half-width (.DELTA.H) is the most outstanding characteristic of YIG, which leads to minimizing a difference between an input signal and an output signal when used for a magnetostatic wave device. Also, another characteristic of YIG is that a relatively low amount of electrical power causes a saturation phenomenon in relation to an input signal, and by using this characteristic, the YIG single crystal film has been widely used for a magnetostatic wave device such as a limiter or a noise filter. Also, various magnetic garnet single crystal films other than the YIG single crystal film have been similarly used for magnetostatic wave devices.
With respect to the known magnetostatic wave devices using magnetic garnet single crystal films, however, when an input signal has a high frequency, a high amount of electrical power must be input in order to cause the saturation phenomenon.
Therefore, there is a need for a higher performance magnetostatic wave device in which relatively low input electrical power causes the saturation phenomenon even when an input signal has a high frequency.